Of course, this is if you own ALL content. This could change if you are missing packs (or dislike and refuse to do some). But it is not only possible, it is easy to go from 1-20 using the adventure compendium as a todo list without repeating a single quest, and not doing slayers. It's my constant tr place, because I hate repeating the same quests, so boring. I like going from quest to quest.